AES E-Library

AES E-Library

Ultra-Low-Noise Preamplifier for Moving-Coil Phono Cartridges

An ultra-low-noise preamplifier for moving-coil phono cartridges using an input transistor developed in a standard integrated circuit process is presented. A signal-to-noise ratio close to the theoretical maximum is realized by careful design. Criteria are given for the noise parameters of the input device, the feedback network, and the input coupling capacitor. Experimental results are presented for a very simple amplifier configuration, having a signal-to-noise ratio of 71 dB for 10 cm/s with a low-sensitivity 14 µV (cm/s) cartridge. Output signals up to 200 mV can be handled, while the distortion is still extremely low (total harmonic distortion - 0.02%).